1. Technical Field
This patent application is directed to the field of video conferencing and broadcasting systems. More specifically, the invention described herein provides a system and method for conducting a video conference or broadcast (each referred to as a video communications session) over a distributed network in which audio and video signals generated by one or more participants in the video communications session are transported via the network.
2. Description of the Related Art
Videoconferencing systems are known. These systems can be implemented over a network that transmits either analog or digital signals. Multiple users can communicate with each other through these systems using a combination of hardware and software, such as a personal computer having a specialized videoconferencing application. These known systems are built so that all of the audio and video signals (A/V signals) from each of the users are transferred through a central control point and then distributed out to the hardware/software system resident at each user's location. The central control point retrieves A/V signals from each of the participants in the video conference, combines these signals into a single data stream, and then transmits the combined data stream of A/V signals to each of the participants. Each participant in the video conference then receives the same feed as every other participant from the central point in the system.
In order to interpret the A/V data stream transmitted from the central control point to the user machines, each participant typically requires a special-purpose application resident on his video conference hardware (i.e., personal computer). The special-purpose application is typically installed on the user's machine prior to participating in a video conference. The special-purpose application typically requires a significant amount of local storage in order to be properly installed at the user's machine, and this storage is then lost to the special-purpose application regardless of whether the user is presently participating in a video conference.
Furthermore, in these known systems, each participant must retrieve the appropriate special-purpose application prior to participating in a video conference. Each time a new version of the application is introduced, each of the participants must adapt to the software change by downloading and installing the new version. Otherwise, within each video conference, different software applications may be implemented and A/V signals must be directed to different software applications.
These known systems suffer from many disadvantages. First, the central control unit is expensive and does not scale well beyond its initial capabilities. The central control unit is involved in computationally intensive processing of all the A/V signals, administering the video conference, and controlling the A/V signal flow, therefore this control unit may not keep up with the additional load if the number of concurrent video conferences increases. As the number of participants in a video conference increases, the required processing power at the central control unit dramatically follows. In addition, the limited ability of the central control unit to organize, manage, and direct all of the video conferences, may create a bottleneck when used on broadband networks. Second, these systems are also limited by storage constraints of the user's hardware, particularly when the hardware includes handheld devices and PDAs, in which memory storage space is at a premium. Because the special-purpose application must be installed on the user machine, which may not have enough storage space to hold the application, these known systems are typically only used with desktop or workstation machines that have ample memory storage. Furthermore, participants that have loaded the special-purpose application into their machines prior to the video conference are likely to encounter compatibility problems because of different video conference applications or different versions of the same application.